The present invention relates to an endoscopic instrument used to harvest body tissue such as a saphenous vein or other blood vessels for use in surgery to graft a harvested vessel into another site within a body, such as in a coronary bypass.
An instrument used to harvest blood vessels is known from Japanese Unexamined Patent Application Publication 2006-000485 (which is priority for U.S. patent application publication 2006/0206112A1). This conventional body tissue harvesting instrument is used in order to dissect veins from surrounding tissue and then to sever and remove the veins from inside the human body.
For example, in coronary bypass operations on blood vessels surrounding the heart, after the diseased (i.e., occluded) part of the blood vessels is identified, a portion of vein harvested from the patient's leg is used to create an alternate pathway for blood to perfuse the artery distally of the diseased vessel, thus making a bypass. When harvesting veins from a leg of the human body, it is frequently the case that a portion of the saphenous vein extending along the leg between the groin and the ankle is harvested.
The work of harvesting this portion of vein is conducted as follows. First, with the patient under general anesthesia, a skin incision followed by blunt dissection at the incision site is performed in the knee area of the leg. Next, a trocar is set in this opening and an elongated dissector (which is a blood-vessel dissecting instrument for separating the vessel from surrounding tissue) is inserted into the leg via the trocar. The insertion part of an endoscope is removably attached to the dissector, which is also provided with a channel for a fluid such as, for example, carbon dioxide gas. Under observation by this endoscope inserted near the knee, and sequentially working along the saphenous vein in two opposite directions (i.e., from the knee to the groin and then from the knee to the ankle), the aforementioned desired portion of the vein is separated and isolated from its surrounding tissue together with multiple small venous branches from the aforementioned desired vein portion. During this time, the aforementioned CO2 fluid is emitted from the tip of the dissector, creating a cavity around the tip of the dissector inside the leg, thereby facilitating observation of the tip of the dissector by the endoscope.
Next, the dissector is removed from the leg interior, and in its place the surgeon or medical technician inserts an insertion member of a blood-vessel harvesting apparatus into the leg via the trocar. The insertion part of an endoscope is removably attached to the insertion member of the harvester, which is also provided with a channel for a fluid such as, for example, carbon dioxide gas. A blood-vessel holder is retractably provided at the tip of this insertion member, which is also provided with a retractable blood-vessel cutter. Operations including forward and backward movement of the blood-vessel holder at the aforementioned tip are made feasible by a blood-vessel holder manipulation member on a handle provided at the proximal end of the insertion member and which is exposed to outside space from the trocar. Operations including forward and backward movement of the blood-vessel cutter at the aforementioned tip are made feasible by a blood-vessel cutter manipulation member on the handle provided at the proximal end of the insertion member and which is exposed to outside space from the trocar.
While observing the aforementioned desired portion of vein via the endoscope, the blood-vessel holder manipulation member and/or the insertion member is manipulated by the surgeon or technician, and the aforementioned desired portion of vein is held by the blood-vessel holder. Furthermore, by manipulating at least one of blood-vessel holder manipulation member, insertion member, and blood-vessel cutter manipulation member, the aforementioned multiple small venous branches protruding from the desired portion of vein are sequentially cut by sequential use of the blood-vessel cutter, working from the knee to the groin and then from the knee to the ankle. The blood-vessel cutter is configured so as to simultaneously cut and cauterize blood vessels by means of application of a high-frequency current to generate extreme heat in a very localized area. During this time, the aforementioned fluid is emitted from the tip of the insertion member, creating a cavity around the tip of the insertion member inside the leg, and thereby facilitating observation of the tip of the insertion member by the endoscope.
When cutting of all of the aforementioned multiple small venous branches from the aforementioned desired portion of vein is completed, incisions are made at the surface of the leg in the respective regions of the groin and the ankle corresponding to the two ends of the aforementioned desired portion of vein in order to expose the two ends of the aforementioned desired portion of vein. Next, the two exposed ends of the aforementioned desired portion of vein are ligated, after which the two ends of the aforementioned desired portion of vein are cut on the inner side of the ligature position. The incisions in the groin and the ankle are then closed with, for example, adhesive plaster or the like. The aforementioned desired portion of vein whose two ends have been cut is extracted from the central opening in the knee, and this opening is finally closed with, for example, suturing adhesive plaster or the like.
The desired portion of vein harvested in this manner undergoes a check for the existence of perforations or lesions in the vascular wall, after which the portions free of perforations and lesions in the vascular wall are used in the aforementioned bypass operation.
The blood-vessel cutter of the conventional elongate body tissue harvesting instrument disclosed by Japanese Unexamined Patent Application Publication 2006-000485 contains a cutter which possesses a slit whose tip opens in a V-shape, with two electrodes disposed along the two side edges of the slit at the base end of the slit and the outer surface of the cutter. Here, the blood vessels captured in the tip of the slit which is opened in a V-shape are flattened by the slit while being moved to the base end of the slit, and in this state are burnt through by the high-frequency current which flows between the aforementioned two electrodes, whereby the cut portion is clotted (i.e., cauterized).
With respect to body tissue harvesting instruments for use in narrow places inside the body, there is constant demand for the ability to conduct more precise harvesting of body tissue in a shorter time, and with simpler operations.